鱼腥藻类囊体膜及其性质的研究

研究了鱼腥藻(Anabaena azollae Strasb.)的光合膜及其性质,结果如下:(1)以培养液为反应介质,测出鱼腥藻细胞的光合放氧,这种放氧受电子传递抑制剂DCMU的抑制。1mmol/L的NH_4Cl既延迟光合放氧的诱导期又抑制光合放氧速率。(2)在700～300nm波长范围,鱼腥藻出现4个吸收高峰,分别位于680、625、480和440nm处。其中625nm的吸收峰应属蓝绿藻的特有吸收峰。(3)通过高压氮气破碎法,并结合超声波处理,可以破碎鱼腥藻细胞壁,并从中分离出鱼腥藻类囊体膜制剂。测定表明,这种膜制剂具有进行光合磷酸化的能力,同时亦有膜上ATP酶水解ATP的能力。(4)利用此膜制剂,分离并部分纯化出ATP酶,在SDS-PAGE图谱上,此酶的两种小亚基(δ和ε亚基)的分子量分别低于菠菜叶绿体ATP酶的δ和ε亚基,但两种酶的α和β两种大亚基的分子量相近。以上结果提示,鱼腥藻具有进行光合作用的内在机构,这种机构在组分及其性质上与其它种类光合膜的异同是值得深入研究的课题。

STUDIES ON PHOTOSYNTHETIC MEMBRANE AND ITS CHARACTERIZATION IN ANABAENA AZOLLAE

Photosynthetic properties of thylakoid membrane of Anabaena azollae Strasb. were characterized as followed: (1) Photosynthetic O2-evolution of the thylakoid cells were measured when various culture fluids were used as reaction media. It was found that induction of the photosynthetic O2-evolution was delayed by NH4Cl and the rate of that was inhibited by both NH4Cl and DCMU (an electron transport-inhibitor). (2) The absorption spectra of A, azollae cells in the range of 700~300 nm exhibited four higher peaks at 680, 625,480 and 440 nm. Among which the peak of 625 nm must be an essential absorption peak of blue-green azollae. (3) The cell walls of A. azollae cells can be broken by Yada and sonication through which the thylakoid membranes were isolated. The preparation of membranes showed the abilities of cyclic photophosphorylation and the activity of membrane-bound ATPase. (4) ATPase were isolated and partially purified from the thylakoid membrane . The pattern of SDS-PAGE showed that molecular weights of the and subunits in the ATPase from A. azollae thylakoid membrane were less than the molecular weights of and subunits in the ATPase from thylakoid membrane of spinach chloroplasts. However, the molecular weights of a and subunits in these two ATPase preparations were similar.